Method of securing a quick-install seat switch

ABSTRACT

A safety switch assembly for deactivating a motor vehicle if a user is not positioned on a vehicle seat. The assembly includes a base for mounting a switch, a cover that moves in response to the presence of a vehicle operator on the seat, and an actuator that moves with the cover to open and close switch contacts inside a switch housing. The base is constructed to pass through a cutout in a vehicle seat pan and includes extensions that also pass through the cutout. The projections are inhibited from movement back through the cutout after the base is rotated from an orientation that allows the projections to be inserted through the cutout to an orientation in which the projections overlie the seat pan.

This is a division of application Ser. No. 08/097,518, file Jul. 27,1993 now U.S. Pat. No. 5,424,502.

FIELD OF THE INVENTION

The present invention concerns a seat switch for use on a ridingutility. vehicle and more particularly for a seat switch for use withlawn and garden tractors having a blade or power take off connections.

BACKGROUND ART

It is common in the prior art to equip a lawn or garden tractor with aseat switch that allows the operator's presence on the seat to bemonitored. If the lawn or garden tractor is running and the operatorsteps off the tractor, there is a danger that the operator will beseriously injured by the blade or the power take off of the tractor. Toreduce the hazard of such serious accidents electrical circuits are usedto disable the engine if the tractor's blade and/or power take off isengaged and the operator steps (or falls) from the tractor seat. Oneexample of such a circuit is found in prior art U.S. Pat. No. 5,190,019to Harvey which issued on Mar. 2, 1993.

The '019 Harvey patent discloses a seat switch that in combination withother switches forms a circuit that can disable a magneto energizedspark plug on a lawn or garden tractor. The seat switch of the Harveypatent is of a design that is closed when the operator is seated on theseat and opens in the event the operator leaves the seat. As noted inthe Harvey patent; the circuit does not necessarily deactivate theengine but does so if a dangerous situation is sensed. The disclosure ofthe Harvey patent is incorporated herein by reference.

Normally open switches suitable for use in the circuit disclosed in theHarvey '019 patent are known in the prior art. U.S. Pat. No. 4,839,478to Howard discloses a push button switch having a push in plunger thatactuates the switch. For a normally open switch, actuation of theplunger causes the switch contacts within a switch housing to be bridgedby a conductive spring that is biased against inner, opposed surfaces ofthe switch contacts. The disclosure of the '478 patent to Howard isincorporated herein by reference.

U.S. Pat. No. 4,795,865 to Howard which issued on Jan. 3, 1989 disclosesa safety switch mounting assembly for positioning a switch on a seatpan. The assembly includes a base for mounting the assembly, a coverthat moves in response to the presence of a vehicle operator on the seatand an actuator that moves with the cover to open and close switchcontacts inside an actuator housing. The contacts of the switch can benormally open or normally closed. The disclosure of the '865 patent toHoward is incorporated herein by reference. The seat switch base shownin the '865 patent to Howard includes two holes that extend through thebase and allow the base to be mounted to the seat pan.

U.S. Pat. No. 5,124,512 to Huettner et al discloses a seat assembly fora utility vehicle. The seat base assembly includes a base portion, aseat cushion and a switching device for switching on and off anelectrical circuit.

U.S. Pat. No. 3,829,803 to Maeda discloses a detecting device thatincludes a pressure receiving member and a magnetically actuated switchcoupled to a bracket that supports the pressure receiving member. Thedevice is mounted on a seat spring of a vehicle seat. The so calledpressure receiving member is coupled to a bracket that engages a vehicleseat spring. The engagement between the bracket and the pressurereceiving member is via a bayonet coupling .

DISCLOSURE OF THE INVENTION

The present invention concerns a switch assembly for use in mounting aswitch to a vehicle seat, typically for a vehicle such as a riding lawnmower, garden tractor or the like. The invention includes structure thatengages a seat pan having a cutout configured to accommodate a base thatsupports an operator-actuated switch. The cutout is preferably generallycircular with radial extending notches that extend through the seat pan.The switch apparatus includes a switch base having a wall with an outerperimeter dimensioned to allow the base to be pushed through the seatpan cutout from beneath the seat.

A number of seat pan engaging members extend radially from the wall ofthe base. They are of a size and are spaced around the periphery of thebase to allow the pan engaging members to be inserted through thenotches in the seat pan, pushed through the cutout, and rotated tosecure the base to the seat pan. The base is coupled to the seat panwith a seat switch already mounted to the base. An actuator extends awayfrom a switch housing and rises above the seat pan in a space betweenthe seat pan and a seat cushion that closes and opens the switch as theoperator gets on and off the vehicle.

A preferred use for the seat switch is to de-activate the vehicleengine. A seat cushion carried by the seat is spaced above the actuatorwhen the vehicle seat is unoccupied. When an operator sits on the seat,the cushion is deformed, bringing a bottom surface of the cushion intocontact with the switch actuator to close normally open contacts withinthe seat switch.

Use of the disclosed apparatus facilitates mounting of the seat switchand requires no special connectors or installation tools. The seat panis manufactured with an appropriately configured cutout and the seatswitch elements mounted to the seat pan by a simple insertion androtation of the switch assembly. In the event the seat switch must bereplaced, it can be removed from the seat without moving the seatcushion.

A simple and easy-to-install seat switch assembly is one object of thepresent invention. This and other objects, advantages and features ofthe invention will become better understood from a detailed descriptionof a preferred embodiment of the invention which is described inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially sectioned side view of a vehicle seat including aswitch assembly constructed in accordance with the invention;

FIG. 2 is an exploded perspective view of the switch assembly showingthe manner in which the assembly is inserted through a cutout in a seatpan;

FIG. 3 is a perspective view showing the switch assembly mounted to aseat pan;

FIG. 4 is a partially sectioned side view on an enlarged scale showingthe preferred construction of the seat switch assembly;

FIGS. 5 and 6 are plan views as seen from beneath the seat pan showinginsertion of the switch assembly into a seat pan cutout and subsequentrotation of the switch assembly to secure the switch assembly to theseat pan; and

FIG. 7 is an elevation view of the switch assembly.

BEST MODE FOR PRACTICING THE INVENTION

Turning now to the drawings, FIG. 1 illustrates a switch assembly 10mounted to a seat 12 such as a riding lawn mower seat or garden tractor.The seat 12 shown in FIG. 1 is constructed of a seat pan 14 of metal orrigid plastic covered with a pliable cushion 16. The switch assembly 10has a movable switch cover 18 that moves to close a switch contact inthe ignition circuit of the vehicle when the seat cushion 16 isdistorted by the weight of an operator.

The switch assembly 10 is connected to the seat pan 14 by a switchassembly base 20. The switch cover 18 is connected to the base 20 andextends above an upper surface of the seat pan 14. When the seat isunoccupied, the cushion 16 defines a generally concave lower surface 16aspaced from the cover 18.

Integral with the cover 18 are three equally spaced flexible andresilient legs 24 that connect the cover 18 to the base 20. Note, onlytwo of the legs 24 are visible in the perspective view of FIG. 2. Thethree legs 24 have flanged ends 24a that fit through three equallyspaced openings 26 (FIG. 5) that extend through the base 20 to a bottomsurface 21. The legs 24 are flexed inward as the flanged ends 24a arepushed through the openings 26. In an unstressed or unflexed position,the legs are generally perpendicular to a cover surface 18a. After thelegs 24 are flexed inward and pushed into the openings 26, they arereleased and return to their original shape. An outwardly facing portionof the flanged ends 24a overlaps a bottom surface 21 of the base 20 toretain the cover and limit its movement away from the base.

With the cover 18 mounted to the base 20, a downward facing lip or edge28 of the cover 18 is positioned above a circular recess 30 betweeninner and outer walls 31, 32 in the base 20. As a vehicle operator sitson the cushion 16, the cushion contacts the cover 18 and moves it towardthe base 20 so that the lip or edge 28 fits within the circular recess30.

The wall 31 defines the outer extent of a central hub portion 40 thatdefines an opening 42 in the base. A switch 43 fits within the opening42 and includes a switch housing 44 supported by the base hub portion40. The switch housing 44 forms an enclosure containing a switchingmechanism. A housing cover 45 is attached to the housing 44 by heatsealing or welding. The housing 44 encloses a compressed spring thatbiases an actuator 46 through an opening in the cover 45. When a vehicleoperator is seated on the seat 12, the weight of the operator deformsthe cushion 16 causing the cushion to push the cover 18 downward andforce the switch actuator 46 to move.

One wall 44a of the actuator housing 44 has openings to accommodate twometallic switch contacts 47 oriented parallel to each other that extendoutside the housing 44. Connectors 48 are slid onto the contacts 47 andelectrically couple the switch 43 to a circuit by means of conductors50.

The switch cover 45 overlaps the housing 44 to define a lip 52 thatextends around the cover and is disrupted by two notches 54, 55. thenotches 54, 55 are positioned to orient the switch with respect to theinner hub portion 40 to fit into the notches. The lip 52 rests against anarrow slot 62 that extends around the opening 42 in the hub andsupports the switch as it is welded to the base 20. The base alsoincludes a guide 70 having openings 72, 74 into which the switchcontacts 47 extend. Additional details concerning the switch mechanismsupported within the housing 44 are disclosed in the '865 patent toHoward.

Turning now to FIG. 2, the seat pan 14 defines a cutout 100 to allow theswitch assembly 10 to be pushed up through the pan 14 and secured to theseat pan by rotation of the switch assembly 10. The preferred cutout 100includes three radially extending notches 110, 112, 114 that allow seatpan-engaging portions of the base 20 to be pushed through the notches.

In the preferred design, there are a total of six seat-engaging portions120, 122, 124, 126, 128, 130 integral with the base 20. A first seatpan-engaging portion 120 is a generally oblong shaped land having acurved radially outer facing surface 132, a top surface 134 co-extensivewith an upper edge. 133 of the cylindrical wall 32, a bottom surface 135which engages the seat pan 14 after the assembly 10 is pushed throughthe seat pan cutout 100, and first and second side surfaces 138, 140which extend radially away from the wall surface 32.

A second pan-engaging portion 122 includes an oblong land having acurved outer surface 150, top and bottom surfaces 152, 154, and firstand second side surfaces 156, 158. Extending away from the side surface158 is an arm 160 having a circular prong 162 which extends below thebottom surface 154. As seen in FIG. 2, the seat pan 14 includes threeholes 170, 172, 174 spaced around the outside edge of the cutout 100that extend through the seat pan. The prong 162 at the end of the arm160 fits within the hole 170 of the seat pan 14 as the switch assembly10 is mounted to the seat pan.

By referring to FIG. 2, it is seen that the radially extending slots inthe seat pan are not identical. The slots 110, 112 are generally thesame shape, having edges E that extend radially outward from acenterline of the seat pan cutout. The third slot 114, however, hasedges 114a, 114b that are not radial, but instead slant at an acuteangle with respect to a radial line passing through vertices between anouter edge of the cutout 100 and an edge of the cutout.

The difference in shape of the notches assures that the switch assembly10 is inserted through the cutout 100 in only one orientation. As seenin FIG. 2, only the seat pan-engaging portions 128, 130 will fit throughthe notch 114 since sides 180, 182 of the two portions 128, 130 slant atacute angles with respect to the radial direction. Trying to push thetwo portions 120, 122 through the notch 110 will cause the seatpan-engaging portions to abut the seat pan and prevent insertion of theswitch assembly 10.

The exploded view shown in FIG. 2 shows the base 20 of the switchassembly 10 oriented for insertion through the cutout 100. Prior tomounting, the cover 18 and switch housing 44 have been mounted to thebase 20. The cover 18 is also attached by flexure and insertion of thelegs 24 into the openings in the base. When so oriented, the assembly 10is installed by pushing the base through the cutout 100 until threeequally spaced gripping members 200, 210, 220 abut the bottom surface ofthe seat pan. The base 20 is then manually rotated in a clockwisedirection (as seen from beneath the seat pan) until two stops 230 engagesides of the cutouts 112, 114. As the base 20 is rotated, the arms 160flex away from the position shown in FIG. 2 and the prongs 162 ride overthe surface of the seat pan as the base 20 is rotated.

When the stops 230 are reached, the prongs are positioned over the holes170, 172, 174 extending through the seat pan so that the prongs fit intothese holes. This prevents the assembly 10 from rotating back to theinsertion position where the assembly 10 could be pushed back throughthe pan cutout.

Each of the gripping member 200, 210, 220 extends radially outwardfarther than the members 120, 122, 124, 126, 128, 130. An outer surface200a of the member 200 is seen in FIG. 2 to be disrupted at regularintervals by elongated ribs 232 which make the member 200 easier tograsp Similarly, the member 210, 220 have ribs 232 extending away fromtheir outer surfaces 210a, 220a. As seen in FIG. 6, the gripping members200, 210, 220 have, radial and circumferential walls 240, 242 so thatthe bottom surface 21 of the base 20 extends to the outer wall 242. Asseen most clearly in FIG. 7, there is a gap G between the grippingmembers 200, 210, 220 and the members 120-130. This gap G is slightlygreater than the thickness of the seat pan.

Once the switch assembly has been mounted to the seat pan, connection ofthe switch to external circuitry for de-activating the vehicle engine isaccomplished by making electrical connection between the conductors 50and the switch contacts 47.

Removal of the switch assembly 10 is accomplished by pressing inward onthe three prongs 162 from beneath the seat pan to flex the arms 160inward while simultaneously grasping the members 200, 210, 220 androtating the base 20 counterclockwise (as seen from below). This causesthe prongs to become misaligned with the holes passing through the pancutout. Once the prongs 162 are rotated away from the holes, continuedrotation of the base is accomplished by sliding the prongs over theupper surface of the seat pan until the pan-engaging members are againaligned with their appropriate notches. The seat switch assembly thencan be pulled back out of the cutout for repair or replacement of theswitch assembly 10.

The present invention has been described with a degree of particularity,but it is the intent that the invention include all modifications fromthe disclosed preferred design falling within the spirit or scope of theappended claims.

I claim:
 1. A method for mounting a seat switch assembly to a vehicleseat comprising the steps of:a) providing a base for supporting the seatswitch assembly on a seat pan, said base having a cylindrical outersurface with circumferentially spaced projections extending radially outfrom the cylindrical outer surfaces; b) mounting the seat switchassembly to the base so that a plunger extending out of a seat switchhousing faces away from the seat pan in a position to be actuated whenan operator sits on the vehicle seat; c) orienting the base in relationto a cutout provided in the seat pan having notches around the peripheryof the cutout so that the projections extending from the base align withthe notches in the cutout; d) pushing the base through the cutout in theseat pan until the projections pass through the seat pan; and e)rotating the base with respect to the seat pan to move the projectionsfrom an alignment position with respect to the notches in the cutout topositions overlying the seat pan.
 2. A method of securing a seat switchassembly to a seat switch pan, said seat switch pan including a cutouthaving a central portion and a plurality of slots extending outwardlyfrom said central portion, said seat switch assembly including a basehaving a switch actuator extending therefrom, said base including afirst portion and second portion spaced apart from said first portion,said first portion including a plurality of outwardly extendingprojections sized to pass through the cutout slots when said base is inan alignment position with respect to said seat pan cutout, said secondportion of said base sized to abut said seat pan when said upper portionis passed through said seat pan cutout, the steps of the methodcomprising:a) positioning the base in the alignment position; b)inserting the base through the seat pan cutout until the second portionof the base abuts the seat pan; and, c) rotating the base with respectto the seat pan to move the projections on the base away from thealignment position.
 3. A method of securing a seat switch assembly to aseat switch pan as set forth in claim 2 wherein the seat panadditionally includes an aperture and said first portion of said baseincludes an extending prong adapted to fit into said aperture andfurther wherein step (c) of the method additionally includes the substepof rotating the base until said prong is positioned in said seat panaperture thereby preventing further rotation of the base with respect tothe seat pan.
 4. A method for mounting a seat switch assembly to avehicle seat pan having an irregular shaped cutout, the seat switchassembly including an upper portion having a cross sectional shapecorresponding to said seat pan cutout and a lower portion spaced apartfrom said upper portion, said lower portion having a cross sectionalshape different than said cross sectional shape of said upper portion,the steps of the method comprising:a) orienting the seat switch assemblysuch that the upper portion is aligned with the seat pan cutout forinsertion through the cutout; b) pushing the seat switch assembly upperportion through the seat pan cutout such that the lower portion abutsthe seat pan; and, c) rotating the seat switch assembly with respect tothe seat pan such that at least a part of the seat switch upper portionoverlies a portion of a first surface of the seat pan and at least apart of the seat switch lower portion overlies a portion of a secondsurface of the seat pan.
 5. The method of mounting a seat switchassembly to a vehicle seat pan as set forth in claim 4 wherein the seatpan further includes at least one aperture and the upper portion of theseat switch assembly includes an extending prong adapted to fit intosaid aperture and wherein the step (c) of the method includes thesubstep of rotating the switch assembly until said prong is insertedinto said aperture thereby preventing further rotation of the seatswitch assembly.